Allen and Wheelock center hammer .44 lipfire, trigger guard operates the cartridge ejector. This particular example was converted to centerfire, very easy conversion, just modify the hammer and turn the back of the cylinder flush with the lip notches. Made by a famous American maker with less than 275 manufactured. Production was ceased due to legal action by Smith and Wesson for patent infringement on their bore through cylinder/Rollin White patent. Circa 1859